1. Field of the Invention
The present invention relates to a receiver for use in a cellular phone or the like, an intermittent frame synchronizing method and a portable remote terminal using the receiver and the method, particularly to a receiver, an intermittent frame synchronizing method and a portable remote terminal which can reduce power consumption and cost.
2. Description of the Related Art
Recently, a cellular phone and a mobile radio communicator such as a pager have been provided with a clock function, a telephone directory function and other high level functions.
On the other hand, in order to realize a long time use with a battery with a limited capacity, power consumption is reduced in various methods. Such method for reducing the power consumption is called battery saving.
For example, at a time of waiting, the battery saving is realized by supplying no power to a receiver at times other than a time when a signal is transmitted from a base station or by other measures. The method of battery saving at the time of waiting has been developed by noting that the signal transmitted from the base station is divided into time units called frames, and is also referred to as xe2x80x9cthe intermittent frame synchronizing methodxe2x80x9d.
In the conventional intermittent frame synchronizing method, an exclusive crystal oscillator is used to generate a clock, and a time when the frame to be received reaches (intermittent reception timing) is detected based on the signal of the clock.
Moreover, in some conventional portable radiophone, a sleep period during which no paging information is received from a remote transceiver is calculated based on a low frequency oscillator and the previous received timing information in the control mode. During the sleep period, a part of the device is shut down, and the power consumption is reduced by intermittently receiving the paging information from the remote transceiver (Japanese Patent Application Publication No. 504075/1996).
In the conventional intermittent frame synchronizing method, however, the crystal oscillator exclusive for generating the intermittent timing clock is necessary. When crystal oscillators for MPU and a clock function are included, three crystal oscillators are used in total, which adds to cost. The mobile radio communicator cannot be miniaturized. Moreover, especially when the interval between the frames to be received is long, a high accuracy is requested for. Furthermore, when the clock operates at a high speed, the power consumption cannot be sufficiently reduced.
An object of the present invention is to provide a receiver, an intermittent frame synchronizing method and a portable remote terminal which can reduce power consumption and further cost while maintaining the accuracy of generation of an intermittent reception timing.
The present invention provides a receiver which comprises a slow clock generating means for outputting clock signals; an averaging means for dividing the clock signals transmitted from the slow clock generating means with separate periods, averaging the divided clock signals and outputting a slot timing signal to form a pulse signal which rises once in one slot time; a saving counter for incrementing the counted value every time the slot timing signal is received, and outputting a coincidence signal indicative of coincidence when the counted value coincides with the preset value; and a receiving means for performing reception only for one slot time after the coincidence signal is received, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
According to the present invention, in the above-mentioned receiver, the averaging means comprises a slot counter for incrementing the counted value every time the clock signal is received from the slow clock generating means; a first decoder for comparing the counted value of the slot counter with the first preset value and outputting a pulse signal indicative of coincidence upon coincidence; a second decoder for comparing the counted value of the slot counter with the second preset value and outputting a pulse signal indicative of coincidence upon coincidence; and a selector for alternately selecting the pulse signals transmitted by the first and second decoders and transmitting to the outside a slot timing signal to form a pulse signal which rises once in one slot time, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
According to the present invention, the receiver is provided with a time measuring clock, and the slow clock generating means corresponds to the time measuring clock, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
The present invention provides an intermittent frame synchronizing method which comprises the steps of dividing clock signals transmitted from a time measuring clock with separate periods, averaging the divided clock signals, generating slot timing signals to form one pulse signal per slot time, counting the slot timing signals, and performing reception only for one slot time every time the preset constant number is reached, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
The present invention also provides a receiver which comprises a slow clock generating means for outputting clock signals; an averaging means for generating slot timing signals from the clock signals to form a pulse signal which rises once in one slot time; a saving counter for counting the slot timing signals and outputting a coincidence signal when the preset value is counted; a receiving means for performing reception only for one slot time after the coincidence signal is outputted; a control means provided with MPU which is stopped when there is no processing to be performed and restarts processing upon receiving an interrupt signal, and outputting a rapid clock control signal for stopping the generation of a rapid clock when the MPU is stopped; a delay circuit for transmitting the interrupt signal to the MPU when the preset constant time elapses after the coincidence signal is received from the saving counter; and a rapid clock generating means for receiving the rapid clock control signal for stopping the generation of the rapid clock to stop the generation of the rapid clock and receiving the coincidence signal from the saving counter to start the generation of the rapid clock, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
The present invention provides a portable remote terminal which comprises a receiver for receiving a radio signal and demodulating the radio signal to a digital signal; a transmitter for modulating the digital signal to transmit the radio signal; a controller for processing the digital signal; a voice processor for performing conversion of the digital signal and a voice signal; a voice output section for outputting a voice; and a voice input section for inputting the voice. The receiver is provided by the present invention as aforementioned. The clock signal for realizing battery saving can be shared with other clock signals, so that the power consumption and cost can be reduced. Moreover, by using the averaging means, the accuracy of the intermittent reception timing can be maintained.
The present invention also provides a portable remote terminal which comprises a receiver for receiving a radio signal and demodulating the radio signal to a digital signal; a transmitter for modulating the digital signal to transmit the radio signal; a controller for processing the digital signal; a voice processor for performing conversion of the digital signal and a voice signal; a voice output section for outputting a voice; and a voice input section for inputting the voice. The receiver is provided by the present invention as aforementioned. In the portable remote terminal, the clock signal for realizing battery saving can be shared with other clock signals, so that the power consumption and cost can be reduced. Moreover, by averaging the clock signals divided with separate periods, the accuracy of the intermittent reception timing can be improved.
The present invention further provides a portable remote terminal which comprises a receiver for receiving a radio signal and demodulating the radio signal to a digital signal; a transmitter for modulating the digital signal to transmit the radio signal; a controller for processing the digital signal; a voice processor for performing conversion of the digital signal and a voice signal; a voice output section for outputting a voice; and a voice input section for inputting the voice. The receiver is provided by the present invention as aforementioned. The clock signal for realizing battery saving can be shared with a time measuring clock signal, so that the power consumption and cost can be reduced, while the accuracy of the intermittent reception timing can be maintained.
The present invention provides a portable remote terminal which comprises a receiver for receiving a radio signal and demodulating the radio signal to a digital signal; a transmitter for modulating the digital signal to transmit the radio signal; a controller for processing the digital signal; a voice processor for performing conversion of the digital signal and a voice signal; a voice output section for outputting a voice; and a voice input section for inputting the voice. The receiver is provided by the present invention as aforementioned. The clock signal for realizing battery saving can be shared with other clock signals. Moreover, while there is no processing to be performed, the supply of the clock signal to MPU can be stopped, so that the power consumption and cost can be reduced. By using the averaging means, the accuracy of the intermittent reception timing can be maintained.
The present invention provides a receiver which comprises a slow clock generating means for outputting clock signals; an averaging means for generating slot timing signals from the clock signals to form a pulse signal which rises once in one slot time; a saving counter for counting the slot timing signals and outputting a coincidence signal when the preset value is counted; a receiving means for performing reception only for the preset one slot time after the coincidence signal is outputted; a control means provided with MPU which is stopped when there is no processing to be performed and restarts processing upon receiving an interrupt signal, and outputting a rapid clock control signal for stopping the generation of a rapid clock when the MPU is stopped; a delay circuit for transmitting the interrupt signal to the MPU when the preset constant time elapses after the coincidence signal is received from the saving counter; and a rapid clock generating means for receiving the rapid clock control signal for stopping the generation of the rapid clock to stop the generation of the rapid clock and receiving the coincidence signal from the saving counter to start the generation of the rapid clock. The averaging means comprises a slot counter for incrementing the counted value every time the clock signal is received from the slow clock generating means; a first decoder for comparing the counted value of the slot counter with the first preset value and outputting a pulse signal indicative of coincidence upon coincidence; a second decoder for comparing the counted value of the slot counter with the second preset value and outputting a pulse signal indicative of coincidence upon coincidence; and a selector for alternately selecting the pulse signals transmitted by the first and second decoders and transmitting to the outside the slot timing signal to form the pulse signal which rises once in one slot time. The receiving means comprises a SW detector for detecting a sync word from the received signal and outputting a pulse signal indicating that the sync word is detected; and a slot counter for receiving the pulse signal from the SW detector and measuring the preset one slot time before outputting an end timing signal. The clock signal for realizing battery saving can be shared with other clock signals. Moreover, while there is no processing to be performed, the supply of the clock signal to MPU can be stopped, so that the power consumption and cost can be reduced. Furthermore, by averaging the clock signals divided with separate periods, the accuracy of the intermittent reception timing can be enhanced.
The receiver of the present invention comprises a plurality of SW detectors corresponding to a plurality of communication systems.
The control means comprises a storage section for storing sets of data to be set in the first decoder, the second decoder, the saving counter and the slot counter corresponding to the plurality of communication systems. The MPU refers to the storage section based on a signal transmitted from the outside for selecting the communication system to select the set of data corresponding to the selected communication system, sets the data contained in the set to the first decoder, the second decoder, the saving counter and the slot counter, and selects and operates the SW detector corresponding to the selected communication system from the plurality of SW detectors. By generating the intermittent reception timing corresponding to the communication system selected from the plurality of communication systems, signals of the plurality of communication systems can be intermittently received by one receiver, so that the power consumption and cost can be reduced, while handiness can further be enhanced.
The present invention provides a portable remote terminal which comprises a receiver for receiving a radio signal and demodulating the radio signal to a digital signal; a transmitter for modulating the digital signal to transmit the radio signal; a controller for processing the digital signal; a voice processor for performing conversion of the digital signal and a voice signal; a voice output section for outputting a voice; and a voice input section for inputting the voice. The receiver is provided by the present invention as aforementioned. In the portable remote terminal, by generating an intermittent reception timing corresponding to the communication system selected from a plurality of communication systems, signals of the plurality of communication systems can be intermittently received by one receiver, so that the power consumption and cost can be reduced, while handiness can further be enhanced.
In the portable remote terminal of the present invention, the plurality of communication systems include a personal digital cellular system and a personal handy phone system. Signals of both PDC and PHS systems can be intermittently received with one portable remote terminal, so that the power consumption and cost can be reduced, while handiness can further be enhanced.